Category Archives: Energy training

We’ve had some very enthusiastic feedback from delegates at MAVCON17, the third National Measurement and Verification Conference, which we held on 16 November.

Delegates wrestle with the thorny issue of non-routine adjustments

Adam Graveley of Value Retail for example described it as “a very informative and well-organised conference that provided a great deal of practical insight” .

The event consistently attracts around 70 M&V practitioners who value not only the networking opportunity but also what they call the ‘geek element’ (expert technical papers with extended question-and-answer sessions), group exercises, and a no-holds-barred expert panel discussion for which this year’s theme was “when M&V goes wrong”.

Our keynote speaker was Denis Tanguay, Executive Director of the Efficiency Valuation Organisation, the body responsible for the International Performance Measurement and Verification Protocol (IPMVP). We are planning to run MAVCON again in early November 2018 and are open for offers of technical papers and ideas for group exercises.

We are grateful to our other speakers Dave Worthington, Hilary Wood, Colin Grenville, Steve Barker and Emma Hutchinson and our expert panelists Sandeep Nair, Ellen Salazar and Quinten Babcock. You can read more about them at the conference web site www.MAVCON.uk

We should also acknowledge the venue, the Priory Rooms, for the quality of their service including excellent catering which also drew much favourable comment.

Coefficient of performance: In refrigeration systems, the ratio of output cooling power to input electrical power.

Cogeneration: See Combined heat and power

Colour rendering: How effective a given light source is at allowing discrimination between colours

Colour temperature: Numerical value describing a light source in terms of how ‘warm’ or ‘cool’ it appears

Combined heat and power: Electricity generation in which part of the waste heat is put to use

Compensator: Control device to regulate circulating water temperature in a heating system, reducing temperature when heat demand is low and vice versa

Condensate: Water resulting from the cooling of steam

Condenser: In a refrigeration circuit, the component through which heat is rejected.

Conduction losses: Heat losses through the walls, roof, floors, doors, windows and other solid elements of the building envelope.

Constant temperature: In heating system, regime in which circulating water is maintained at a fixed temperature and control of heat output is effected by regulating flow to heat emitters

Convection losses: Heat lost in air leaving the building through draughts and deliberate ventilation

Convector, fan assisted: Heat emitter on a central heating system in which a fan blows room air across a heat exchanger

Convector, natural: Heat emitter on a central heating system, usually enclosed in a cabinet with inlet and outlet vents, which warms room air without the assistance of a fan

Cooling tower: Device in which water used for cooling something gives up some of its heat to the air, enabling it to be recirculated in a closed loop. May be ‘dry’, employing a sealed heat exchanger, or ‘wet’ in which case evaporation of the water increases the cooling effect

CoP: See Coefficient of performance

Coriolis meter: Technology for measuring the flow rate of for example dust-laden gases; the flow rate affecting the resonant frequency of a U-shaped section of vibrating pipe

Correction factor: In the context of natural gas, the factor by which its metered volume must be multiplied to account for its pressure and temperature being other than that assumed as standard

CT: In heating system: see Constant temperature; in metering see Current transformer

Current: Rate of flow of electrical energy

Current transformer: Device placed around one conductor of an electrical supply cable to convert the current flowing in it into a safely-measurable signal for input to a meter

Dead band: Switching differential between for example the activation of heating and cooling in a space; sometimes in a thermostatic control the spread between temperatures that trigger changes of state each way between on and off.

Degree days: Measure of how hot or cold the weather was over a given interval, typically a week or month, in a given location or region. Used in an analogous fashion to production output as the driving factor for heating opr air-conditioning energy consumption.

Deliquescent: Dessicant material which dissolves in the water it absorbs

Delta: Connection method for three-phase devices where the load is connected from phase to phase without a neutral (cf star)

Demand, maximum: See Maximum demand

Dessicant: Material which absorbs water vapour; used for example in compressed-air dryers

Deviance : Difference between actual and expected consumption

Dew point: Air temperature at which moisture will begin to condense; also known as saturation temperature

Dichroic: Attribute of a filament spotlamp whereby the reflector allows heat to escape through the back

Direct-fired heater: Heater in which fuel is used directly, as distinct from a heat emitter on a hot-water or steam circuit with centralised combustion.

Discounted cash flow: Method of accounting for future expenditure and receipts which explicitly recognises that postponing a cash flow diminishes its value in present terms

Driving factor: Recurrent and measurable determinant of energy consumption, such as production output or degree-day value.

Gross calorific value: Total chemical energy content of a fuel, including what would be recovered by condensing the water vapour from the products of combustion. Also called higher calorific value. Cf Nett calorific value.

Ground-source heat pump: Reverse refrigeration cycle which cools the ground in order to provide a heating effect from its condenser (cf Geothermal energy)

Landfill gas: Methane emanating from waste-disposal sites and collected as a fuel

Latent heat: Heat required to melt or vaporise a substance; or heat released when a vapour condenses or a liquid solidifies. Notwithstanding the release or absorption of heat, the change of state between liquid and solid or vapour occurs without a change of temperature.

Load factor: Ratio between actual output or input and the maximum theoretically possible with continuous operation at full output or input.

Maximum demand: In UK context, the peak electrical power drawn over any half-hour period in a month

Mercury discharge: Type of fluorescent lamp typically used for floodlighting

Metal halide: Type of filament lamp

Mixing valve: In a Variable temperature heating circuit, the valve which regulates flow temperature by blending water from the boiler(s) with cooler water returning from the heating system. Also called a three-port valve as it has two inputs and one output connection.

Monitoring and targeting: Systematic assessment of actual against expected consumption by means of weekly (usually) overspend league table augmented by analysis tools to assist in target-setting and diagnosis of abnormal performance.

Motorised valve: Valve actuated by an electric motor under the dictates of a control system

Passive infra-red: Technique for detecting the presence of people in a space

Performance characteristic: Mathematical relationship between energy consumption and one or more driving factors

Phase: Alternating-current electrical supplies are either single-phase (delivered through one pair of wires) or three-phase (delivered through three wires, the current waveform in each being one-third of a cycle behind or ahead of the others).

PIR: See Passive infra-red

Polyphase: arrangement of electrical supply in which (most commonly) three lines are energised by alternating current one-third of a cycle apart

Power: Rate of flow of energy

Power factor: In alternating-current electrical supplies, the ratio of useful power delivered to the theoretical maximum possible for the given current and voltage

Precision: Degree of resolution in a measurement

Profile: Pattern of demand over a day, week, or other chosen interval.